The Labour chief whip is under investigation by the parliamentary standards commissioner for allegedly misusing confidential information given to him as an MP. The inquiry concerns allegations that Sir Alan Campbell breached rules on the “use of information received in confidence in the course of the Member’s parliamentary duties”, as well as on the use of his parliamentary email address. Kathryn Stone, the parliamentary commissioner for standards, opened the investigation on Wednesday, according to her office’s website. She will examine an allegation that Campbell breached paragraph 15 of the MPs’ code of conduct, which states that: “Information which Members receive in confidence in the course of their parliamentary duties should be used only in connection with those duties. Such information must never be used for the purpose of financial gain.” The Guardian understands the complaint relates to emails alleged to have been sent to a mailing list from a parliamentary email address. Campbell’s team say the emails came from a personal address. A source close to Campbell said that “he and his office are fully complying with the commissioner, and that every precautionary step is always taken to fully comply with the rules”. Allegations that this rule has been breached are rarely investigated by the commissioner. The House of Commons standards committee noted in its November 2021 draft update to the code of conduct that “the Commissioner has not investigated an allegation under this paragraph and is not aware of any predecessor having done so”. In July 2020, Stone considered whether Conservative backbencher Sir Bob Neill had broken paragraph 15 as part of a wider inquiry, but found no evidence that the rule had been breached. Stone upheld an allegation that Neill had failed to declare a commercial interest in correspondence to ministers and public officials, which Neill at the time accepted and apologised for. Proposed changes by the standards committee to the code of conduct would expand the restriction from “financial gain” to “other purposes” beyond parliamentary activities. The government did not make time for the proposals to be debated in the Commons before the summer recess. Chris Bryant, the Labour chair of the committee, told NationalWorld last week that it is “essential that the government commits to providing time for the house to consider our proposals as soon as possible”. Stone is also investigating an allegation that Campbell used his parliamentary email address for purposes other than his parliamentary duties. Such claims are more commonly investigated by the commissioner, who is investigating the same allegation against two other MPs, Labour’s Ian Byrne and former junior DCMS minister Chris Philp. Campbell, the MP for Tynemouth since 1997, was appointed opposition chief whip in May 2021, after serving for nearly 11 years as opposition deputy chief whip from October 2010. Campbell was a government whip from 2006 to 2008. Campbell received his knighthood in the 2019 new year honours list for political service. Stone’s office declined to comment.